<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>标题</title>
  <style>
    #test{
      background-color: aqua;
      height: 100px;
    }
  </style>
</head>
<body>
  <div id="test">
    <h1>hello world</h1>
    

  </div>
</body>
</html>